Assessment of Aerothermodynamic Analysis Methods with Regard to the Planned SHEFEX Flight Experiment

Kurzfassung

Appraisal of aerothermodynamic analysis results is not always easy, because reliable wind tunnel results are often available for the low speed regime only. Therefore, in many cases theoretical analysis may be the only method available in some hypersonic flight regimes. Depending on the amount of experience with similar configurations/hypersonic flight states, or the lack of thereof, a careful selection of appropriate safety factors for the calculated heat loads (and other parameters) is necessary. Obviously, the less sophisticated the analysis method, the more a safety margin has to be applied. In order to improve the analysis tools, to reduce the safety margins required and to allow for a true optimization of hypersonic flight vehicles and re-entry Systems further empirical knowledge is desirable. Increasing the existing experimental aerothermodynamic database from freeflight measurements on actual flight systems remains therefore an important task. The SHarp Edge Flight Experiment SHEFEX initiated by the German aerospace research center DLR will provide such an opportunity. The launch of a two stage suborbital rocket with the experimental vehicle mounted on top is planned in the second half of 2005. The system will reach an apogee of 327 km. The SHEFEX system will then perform a reentry to deliver aerothermodynamic data up to flight Mach numbers between 7 and 8 at altitudes between 90 and 20 km. The paper describes preliminary aerothermodynamic analyses performed at EADS-ST in preparation of the planned SHEFEX post flight assessment. Simplified analysis tools (surface inclination methods combined to boundary layer analysis) as well as CFD-caIculations based on structured and unstructured grids using various turbulence models are considered. First conclusions can be drawn from results using different analysis tools regarding aerothermodynamic parameters such as calculated heat flux densities, surface temperatures and pressure distributions.